Monoclonal antibody, and use thereof

Abstract

[Theme] To provide a monoclonal antibody against human GPR87. Also, to provide a novel means for diagnosing or treating a malignant tumor. [Solution means] Monoclonal antibodies against human GPR87 are provided. The antibodies can recognize human GPR87, which is expressed on a cell membrane while retaining a three-dimensional structure, and can recognize GPR87, which is expressed in a cell endogenously with an epitope being present in an extracellular domain of full-length human GPR87. The antibodies are thus useful in biochemical analysis, etc., of GPR87, useful in immunohistological diagnosis, etc., of squamous cell carcinoma, and also potentially useful in PET diagnosis, antibodies for treatment, etc., of squamous cell carcinoma.

What is claimed is: 
     
       1. A monoclonal antibody that binds specifically to a protein having the same amino acid sequence as sequence No. 1 or a partial peptide of the protein, recognizing an epitope presented in an amino acid sequence of sequence No. 6, comprising a CDR1, CDR2 and CDR3 of an antibody H chain V region having the amino acid sequences set forth in SEQ ID NOS:20, 21, and 22, respectively; and a CDR1, CDR2 and CDR3 of an antibody L chain V region having the amino acid sequences set forth in SEQ ID, NOS:23, 24 and 25, respectively. 
     
     
       2. The monoclonal antibody according to  claim 1 , which is an IgG1. 
     
     
       3. A monoclonal antibody that binds specifically to a protein having the same amino acid sequence as sequence No. 1 or a partial peptide of the protein, recognizing an epitope presented in an amino acid sequence of sequence No. 6which is an antibody produced by hybridoma accession No. NITE BP-668. 
     
     
       4. A hybridoma of accession No. NITE BP-668. 
     
     
       5. A tumor diagnostic agent comprising as an active ingredient the monoclonal antibody according to  claim 1  bound to a detectable label enabling detection, and wherein the antibody binds specifically with human GPR87. 
     
     
       6. The tumor diagnostic agent according to  claim 5 , wherein the detectable label is a radioisotope label and the tumor diagnostic agent can be used as a tumor diagnostic agent for PET. 
     
     
       7. A tumor therapeutic agent comprising as an active ingredient the monoclonal antibody according to  claim 1 , wherein the monoclonal antibody has cellular cytotoxic activity. 
     
     
       8. A tumor therapeutic agent comprising, as an active ingredient, a monoclonal antibody according to  claim 1  that has been conjugated with a cytotoxic substance. 
     
     
       9. A tumor diagnostic agent comprising the monoclonal antibody of  claim 1  that binds specifically with GPR87 on a GPR8-expressing tumor cell of a tumor selected from the group consisting of skin cancers, head and neck cancers, lung cancers, esophageal cancers, cervical cancers, uterine cancers, pancreatic cancers, breast cancers, kidney cancers, ureteral cancers, and bladder cancers. 
     
     
       10. A tumor therapeutic agent for treating a tumor comprising, as an active ingredient, the monoclonal antibody of  claim 1  that binds specifically with GPR87, wherein the tumor is selected from the group consisting of skin cancers, head and neck cancers, lung cancers, esophageal cancers, cervical cancers, uterine cancers, pancreatic cancers, breast cancers, kidney cancers, ureteral cancers, and bladder cancers. 
     
     
       11. The tumor therapeutic agent of  claim 10 , wherein the tumor is selected from the group consisting of prickle cell carcinomas, basal cell carcinomas, melanomas of skin, tongue cancers, squamous cell carcinomas, malignant lymphomas of a pharynx, squamous cell carcinomas of a larynx, squamous cell carcinomas, small cell carcinomas of a lung, squamous cell carcinomas of an esophagus, squamous cell carcinomas of a cervix, uterine adenocarcinomas, transitional cell carcinomas, squamous cell carcinomas of a bladder, and transitional cell carcinomas of a renal pelvis or ureters. 
     
     
       12. Method of determining the presence of an antigen comprising contacting a sample comprising protein, cells or tissue with the antibody according to  claim 1 , and determining whether the antibody binds to the sample. 
     
     
       13. The method according to  claim 12 , further comprising determining whether GPR87 is expressed to determine whether the sample comprises tumor cells. 
     
     
       14. The method according to  claim 12 , wherein the sample comprises breast tissue and determining whether GPR87 is expressed to determine whether cancer cells are present.